Abstract
We stained synaptic vesicles in frog motor nerve terminals with FM1-43 and studied changes in the shape and position of vesicle clusters during nerve stimulation. Each stained vesicle cluster appeared as a fluorescent spot. During repetitive nerve stimulation the spots gradually dimmed, most without changing shape or position. Occasionally, however, a spot moved, appearing in some cases to stream toward and coalesce with a neighboring spot. This suggests the existence of translocation mechanisms that can actively move vesicles in a coordinated fashion between vesicle clusters. Within single clusters, we saw no signs of such directed vesicle movements. Fluorescent spots in terminals viewed from the side with a confocal microscope did not shrink toward the presynaptic membrane during nerve stimulation, but dimmed uniformly. This suggests that vesicles continuously mix within a cluster during destaining and provides no evidence of active vesicle translocators within single vesicle clusters for moving vesicles to the presynaptic membrane.
Original language | English |
---|---|
Pages (from-to) | 805-813 |
Number of pages | 9 |
Journal | Neuron |
Volume | 9 |
Issue number | 5 |
DOIs | |
Publication status | Published - 1 Nov 1992 |
Keywords
- Animals
- Electric Stimulation
- Fluorescent Dyes
- Microscopy, Fluorescence
- Motor Neurons
- Movement
- Nerve Endings
- Rana pipiens
- Synaptic Vesicles